The availability of a bias current source with an accurate and controllable absolute value in CMOS integrated circuits is highly desirable in a wide range of applications. Conventional techniques typically utilize an external resistor to define the value of the bias current. This requires the allocation of a dedicated package pin to connect to the external resistor, which is costly and inefficient. Accurate clock signals, on the other hand, are readily available in digital and mixed analog/digital integrated circuits.
Accordingly, it is an objective of the present invention to provide a bias current generator that generates an accurate bias current using the available clock signals as a reference. It is yet another objective of the present invention to provide a clock-referenced switching bias current generator that is implemented in CMOS technology. It is a further objective of the present invention that the bias current generator satisfy different design goals, including tracking a bandgap voltage to produce an accurate, temperature-insensitive bandgap bias current and generating an anti-process bias current (e.g., a larger current for a circuit fabricated at a slow process corner).